//: :require.h
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 1999
// Copyright notice in Copyright.txt
// Test for error conditions in programs
// Local "using namespace std" for old compilers
#ifndef REQUIRE_H
#define REQUIRE_H
#include <cstdio>
#include <cstdlib>
#include <fstream>

inline void require(bool requirement,
                    const char* msg = "Requirement failed")
{
    using namespace std;
    if (!requirement) {
        fprintf(stderr, "%s", msg);
        exit(1);
    }
}

inline void requireArgs(int argc, int args,
                        const char* msg = "Must use %d arguments")
{
    using namespace std;
    if (argc != args + 1) {
        fprintf(stderr, msg, args);
        exit(1);
    }
}

inline void requireMinArgs(int argc, int minArgs,
                           const char* msg =
                               "Must use at least %d arguments")
{
    using namespace std;
    if (argc < minArgs + 1) {
        fprintf(stderr, msg, minArgs);
        exit(1);
    }
}

inline void assure(std::ifstream& in,
                   const char* filename = "")
{
    using namespace std;
    if (!in) {
        fprintf(stderr,
                "Could not open file %s", filename);
        exit(1);
    }
}

inline void assure(std::ofstream& in,
                   const char* filename = "")
{
    using namespace std;
    if (!in) {
        fprintf(stderr,
                "Could not open file %s", filename);
        exit(1);
    }
}
#endif // REQUIRE_H ///:~
